Add documentation about the migration hack

master
Thibaut Girka 5 years ago
parent 6475525f31
commit 33c2a7e23c
  1. 14
      config/initializers/0_duplicate_migrations.rb
  2. 10
      db/migrate/20180410220657_create_bookmarks.rb
  3. 3
      db/migrate/20180831171112_create_bookmarks.rb

@ -1,3 +1,17 @@
# Some migrations have been present in glitch-soc for a long time and have then
# been merged in upstream Mastodon, under a different version number.
#
# This puts us in an uneasy situation in which if we remove upstream's
# migration file, people migrating from upstream will end up having a conflict
# with their already-ran migration.
#
# On the other hand, if we keep upstream's migration and remove our own,
# any current glitch-soc user will have a conflict during migration.
#
# For lack of a better solution, as those migrations are indeed identical,
# we decided monkey-patching Rails' Migrator to completely ignore the duplicate,
# keeping only the one that has run, or an arbitrary one.
ALLOWED_DUPLICATES = [20180410220657, 20180831171112].freeze
module ActiveRecord

@ -1,3 +1,6 @@
# This migration is a duplicate of 20180831171112 and may get ignored, see
# config/initializers/0_duplicate_migrations.rb
class CreateBookmarks < ActiveRecord::Migration[5.1]
def change
create_table :bookmarks do |t|
@ -7,8 +10,11 @@ class CreateBookmarks < ActiveRecord::Migration[5.1]
t.timestamps
end
safety_assured { add_foreign_key :bookmarks, :accounts, column: :account_id, on_delete: :cascade }
safety_assured { add_foreign_key :bookmarks, :statuses, column: :status_id, on_delete: :cascade }
safety_assured do
add_foreign_key :bookmarks, :accounts, column: :account_id, on_delete: :cascade
add_foreign_key :bookmarks, :statuses, column: :status_id, on_delete: :cascade
end
add_index :bookmarks, [:account_id, :status_id], unique: true
end
end

@ -1,3 +1,6 @@
# This migration is a duplicate of 20180410220657 and may get ignored, see
# config/initializers/0_duplicate_migrations.rb
class CreateBookmarks < ActiveRecord::Migration[5.1]
def change
create_table :bookmarks do |t|

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